From: Michal Soltys <nozo@ziu.info>
To: linux-raid@vger.kernel.org
Cc: Janek Kozicki <janek_listy@wp.pl>
Subject: Re: stride / stripe alignment on LVM ?
Date: Fri, 02 Nov 2007 13:10:07 +0100 [thread overview]
Message-ID: <472B139F.9060903@ziu.info> (raw)
In-Reply-To: <20071101101037.63b523f8@absurd>
Janek Kozicki wrote:
>
> And because LVM is putting its own metadata on /dev/md1, the ext3
> partition is shifted by some (unknown for me) amount of bytes from
> the beginning of /dev/md1.
>
It seems to be multiply of 64KiB. You can specify it during pvcreate, with
--metadatasize option. It will be rounded to multiply of 64 KiB, and will
add another 64 KiB on its own. Extents will follow directly after that. 4
sectors mentioned in pcvreate's man page are covered by that option as well.
So i.e. if you have chunk 1MiB, then pvcreate ... --metadatasize 960K ...
should give you chunk-aligned logical volumes, assuming you have actual
extent size set appropriately as well. If you use default chunk size, you
shouldn't need any extra options.
Make sure if it really is this way, after pv/vg/first lv creation. I found
it experimentally, so ymmv.
prev parent reply other threads:[~2007-11-02 12:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-01 9:10 stride / stripe alignment on LVM ? Janek Kozicki
2007-11-01 23:27 ` Neil Brown
2007-11-02 13:01 ` Bill Davidsen
2007-11-02 22:16 ` Janek Kozicki
2007-11-03 18:40 ` Doug Ledford
2007-11-03 20:21 ` Janek Kozicki
2007-11-04 1:02 ` Doug Ledford
2007-11-07 9:00 ` Goswin von Brederlow
2007-11-11 23:53 ` Alasdair G Kergon
2007-11-07 9:04 ` Goswin von Brederlow
2007-11-02 12:10 ` Michal Soltys [this message]
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